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The presentation of the chloride threshold level for corrosion of steel in concrete
(1) In terms of the currently used representations, chloride threshold levels are best presented as a total chloride content expressed relative to the weight of cement. The hypothesis that in theory a free chloride content or chloride to hydroxyl concentration ratio represents an improvement to this is not supported by the available evidence. Indeed the published data tends to suggest that bound chloride presents some corrosion risk and a high pore solution pH is only one of the inhibitive properties of hydrated cement. (2) It is postulated that bound chloride increases the reservoir of that locally available at the steel-concrete interface. This restricts any fall in the local chloride activity which may result when chloride participates in the corrosion process at an incipient anode. Furthermore, the acidification which occurs at an incipient anode, may promote the release of bound chloride increasing the local chloride activity above its initial value. (3) The most important inhibitive property of the cement appears to be its effective buffering capacity which restricts any local fall in pH to values below 12.6. This suggests that a possible improvement in the presentation of the threshold level may be to express the total chloride content relative to the alkaline reserves of the concrete.
The presentation of the chloride threshold level for corrosion of steel in concrete
(1) In terms of the currently used representations, chloride threshold levels are best presented as a total chloride content expressed relative to the weight of cement. The hypothesis that in theory a free chloride content or chloride to hydroxyl concentration ratio represents an improvement to this is not supported by the available evidence. Indeed the published data tends to suggest that bound chloride presents some corrosion risk and a high pore solution pH is only one of the inhibitive properties of hydrated cement. (2) It is postulated that bound chloride increases the reservoir of that locally available at the steel-concrete interface. This restricts any fall in the local chloride activity which may result when chloride participates in the corrosion process at an incipient anode. Furthermore, the acidification which occurs at an incipient anode, may promote the release of bound chloride increasing the local chloride activity above its initial value. (3) The most important inhibitive property of the cement appears to be its effective buffering capacity which restricts any local fall in pH to values below 12.6. This suggests that a possible improvement in the presentation of the threshold level may be to express the total chloride content relative to the alkaline reserves of the concrete.
The presentation of the chloride threshold level for corrosion of steel in concrete
Vorstellung eines Chlorid-Grenzwertes für die Stahlkorrosion in Beton
Glass, G.K. (author) / Buenfeld, N.R. (author)
Corrosion Science ; 39 ; 1001-1013
1997
13 Seiten, 5 Bilder, 51 Quellen
Article (Journal)
English
The presentation of the chloride threshold level for corrosion of steel in concrete
| British Library Online Contents | 1997
Chloride threshold level for corrosion of steel in concrete
| Tema Archive | 2007
Chloride threshold level for corrosion of steel in concrete
| British Library Online Contents | 2007